[incremental/pm] check for incremental apps when LauncherAppsService starts

If an incremental app is not fully loaded before reboot, we need to keep
showing the loading progress after reboot. Previously we only register
the listener callback when the app is installed. Now we also register
the listener on reboot in LauncherAppsService.

BUG: 182272641
Test: manual
Change-Id: I44af6f5958226ccb1a6229ee28db6227df645996